X-ray magnetic circular dichroism at the Gd L edges in Gd-Ni-Co amorphous systems

X-ray magnetic circular dichroism (XMCD) experiments have been performed at the L(2,3) edges of gadolinium in the amorphous Gd-Ni-Co and Gd-Ni alloys in order to observe the effect of the transition metal on the polarization of the rare-earth 5d band. The magnetic properties of the Gd-Ni-Co alloys, weak anisotropy or perpendicular easy axis of magnetization, are very well suited to XMCD experiments and very large XMCD signals are observed at the Gd L(2,3) edges. The signals corrected from the circular polarization rate (P-c=0.65) can reach up to -22% at the L(2) and +11% at the L(3) for some samples. The V-Like behavior of the XMCD signal at the Gd L edges near the compensation temperature is understood in terms of distribution of the Co concentration in the Gd-Ni-Co sputtered films. Within the spin-dependent radial matrix model, the evolution of the XMCD intensity in the Gd-Ni-Co films as a function of the Co concentration qualitatively accounts for the variation of the spin-dependent final-state density Delta rho/rho monitored by the Co concentration.